Crystallographic investigations on ribosome-associated GTP-binding proteins

Translation of the genetic code is a complex process performed by the ribosome, a 2.5-MDa ribonucleoprotein complex, and its associated factors. To fully comprehend how translation is accomplished requires comprehensive structural and functional analyses of its molecular components at each stage throughout the process. The following work summarizes investigations into the three-dimensional properties of bacterial elongation factor Tu (EF-Tu) and stringent response factor, RelS. Each is a ribosome-associated protein capable of binding guanosine nucleotides, although their cellular roles are quite different. Crystallographic investigations of wild type and mutant complexes of EF-Tu, as described herein, help to provide new insights into the mechanisms of GTP hydrolysis, nucleotide exchange, and macromolecular switching. The successful crystallization, phase determination and preliminary structure analysis of a bifunctional RelS fragment is also detailed.